1. Field of the Invention
This invention relates generally to a microwave module retainer. Specifically, the present invention is directed to a self-adjusting, spring action, module retention device for an active electronically scanned array (AESA), also known as an active aperture.
2. Description of Related Art
In a 4th generation active electronically scanned array (AESA), multiple microwave transmit/receive (T/R) modules are required. The details of such a T/R module is shown and described in related U.S. Pat. No. 6,114,986 entitled xe2x80x9cDual Channel Microwave Transmit/Receive Module For An Active Aperture of A Radar Systemxe2x80x9d which is incorporated herein by reference.
Accordingly, there is an ongoing need to produce T/R modules that are easy to install into an antenna assembly. Such microwave T/R modules are the electronically active components in the antenna assembly and the T/R modules require cooling. As such, the microwave T/R modules are spaced according to the location of the radiating elements to which they connect and are conduction cooled by coldplates.
Such conduction cooling is typically done by rows of parallel coldplates installed in an array. However, due to such a configuration, there is limited space available for installation of additional components. In addition, the microwave T/R modules require positive contact pressure against the coldplate to help facilitate the heat removal from the microwave module. In addition, motion of the T/R modules during operation can cause the RF connectors to disengage. To prevent/limit the motion of the T/R modules, a module retention device is required.
Previous designs of module retention devices included wedgelocks to force the microwave modules into contact with the coldplate by wedging between the lid/ring frame of the microwave module and the adjacent coldplate. Such a wedgelock was developed by the assignee of this invention and is shown and described in U.S. Pat. No. 6,005,531, entitled, xe2x80x9cAntenna Assembly Including Dual channel Microwave Transmit/receive Modules,xe2x80x9d issued on Dec. 21, 1999, and is intended to be incorporated herein by reference.
The wedgelocks disclosed therein grip the sides of each T/R module causing the heat sink plate on the bottom of the module to be pressed tightly against the respective coldplates upon the actuation of screw members which forms part of the wedgelock assemblies. In addition, the load produced by the wedgelocks were not self contained and consequently the loads traveled throughout the antenna assembly, causing the antenna to distort.
In addition, the conventional wedgelock system relied upon friction to generate its module retention load and to retain the module in place. Furthermore, during the assembly process, the wedgelocked antenna was generally subjected to elevated temperatures, and then returned to room temperature. After returning to room temperature, the expansion and contraction of the wedgelock resulted in loose wedgelocks throughout the antenna assembly. The loose wedgelocks required manual tightening since their loads were not self-adjusting.
In addition, with the conventional wedgelocks, when a microwave T/R module is replaced, the wedgelocks must be loosened and removed. When one wedgelock is removed, the entire assembly is affected because of the interdependency between wedgelocks, all of which contribute to the cumulative load that they impart to the assembly.
Hence, there is a need to provide a T/R module retention device that avoids the problems introduced by the conventional wedgelocks.
Accordingly, one aspect of the present invention is to provide an improved retainer device for microwave T/R modules.
It is a further aspect of the present invention to provide an improved retainer device for an active electronically scanned antenna array utilized in connection with phased array radars.
And it is yet another aspect of the invention to provide a module retention device that relies upon a self-adjusting spring configuration to provide a sufficient load.
These and other aspects are achieved by a miniature, self-locking, spring action, microwave T/R module retainer device which includes a retainer body that holds a spring and transfers the spring load to a single coldplate. The spring has a double arch configuration designed to contact an extended heat sink plate located on one side of the microwave T/R module. When in position, the deflection of the double arch spring of the retainer device imparts a force onto the extended heat sink, pressing the T/R module against the coldplate when the module retainer device is installed. Once installed, the retainer device exhibits a self-locking characteristic.
Further, if the location of the T/R module changes due to thermal or mechanical loads, the potential energy stored in the arch spring allows the spring to automatically re-adjust accordingly.
These and other aspects of the invention are realized in one embodiment by an exemplary module retainer body including: an aft latch (or hook); a cantilever arm with latch having a removal tab; a spring retention tab; a spring alignment pad; a forward (bottom) post; and a module excursion stop.
These and other aspects of the invention are further realized in another embodiment by a preferred module retainer body including: a aft latch; a spring retention tab, a spring alignment pad; and a forward (bottom) post.
The module retainer/retention device in each of the embodiments makes contact with the microwave T/R modules at the extended heat sink once the microwave T/R modules have been installed. This is accomplished by inserting/latching the retainer device to the mating features on the coldplate.
Further scope of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be noted, however, that the detailed description and specific examples, while disclosing exemplary embodiments of the invention, is given by way of illustration only. This is due to the fact that various changes, alterations and modifications coming within the spirit and scope of the invention will become apparent to those skilled in the art.